21082687 has 2 divisors, whose sum is σ = 21082688. Its totient is φ = 21082686.

The previous prime is 21082673. The next prime is 21082729. The reversal of 21082687 is 78628012.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21082687 is a prime.

It is a super-2 number, since 2×21082687² = 888959382279938, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21082627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10541343 + 10541344.

It is an arithmetic number, because the mean of its divisors is an integer number (10541344).

Almost surely, 2^21082687 is an apocalyptic number.

21082687 is a deficient number, since it is larger than the sum of its proper divisors (1).

21082687 is an equidigital number, since it uses as much as digits as its factorization.

21082687 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10752, while the sum is 34.

The square root of 21082687 is about 4591.5887228714. The cubic root of 21082687 is about 276.2540500215.

The spelling of 21082687 in words is "twenty-one million, eighty-two thousand, six hundred eighty-seven".